The sewage in New England’s exclusive Nantucket retreat is full of cocaine, according to local authorities, who this summer began testing it to monitor potential drug use in a popular summer getaway for the rich and powerful.

“During COVID, a lot of these communities, and most communities, decided that it was important for them to start testing the water to see if there were any spikes in COVID in the region.” said Randolph Rice, a Maryland attorney and legal analyst. “But what Nantucket has now decided to do as of the beginning of the summer is to actually start testing for other types of substances, particularly drugs, nicotine and other items…within the system there. And what they’re finding is that there is a high level of cocaine.”

The testing, conducted at the Surfside Wastewater Treatment Facility on Nantucket, found cocaine levels about 50% higher than the national average, according to publicly posted data from local authorities. The same tests found below-average levels of fentanyl, a deadly synthetic opioid blamed for overdoses around the country.

Local health officials announced the wastewater testing program would begin earlier this summer. The island’s treatment plant serves about three-quarters of local homes, which authorities said would give them access to “island-wide trends without identifying individuals or neighborhoods” – protecting privacy while giving health officials a glimpse into what’s going on behind closed doors.

Xylazine testing came back with results lower than the minimum observable level. Methamphetamine barely registered.

“What’s shocking is that there is a low level of trace items,” Rice told Fox News Digital. “For example, there is very little fentanyl or xylazine, which is also referred to as ‘tranq.’ Oftentimes, these substances are added to [drugs] to make them more potent, but they also make them deadly. So what it’s telling us in Nantucket, is they’re getting the pure stuff.”

Back in May, local authorities announced what local outlets described as the largest cocaine-related drug bust in Nantucket history.

The suspect was identified as Francisco Fernandez Sanchez, a green card holder from the Dominican Republic, the Nantucket Current reported. He allegedly had more than 5 1/2 pounds of the drug when police searched his residence – worth an estimated $250,000 on the street.

David Katz, a former DEA special agent, told Fox News Digital that the contamination could have come from someone flushing a large amount of drugs to evade authorities.

A general view of the shoreline in Nantucket on Friday, Sept. 27, 2024. (David McGlynn for Fox News Digital)

“We used to shut the water off before we did search warrants because of that same thing,” he said.

Another possibility, he added, would be smaller but frequent flushes from cocaine users as the drug leaves their system in the bathroom.

The latter scenario seems more likely to Rice, he said, because the testing was conducted repeatedly throughout the summer, not just in one go after any particular incident.

“To have consistent days, a consistent test with that level of cocaine spikes, it seems to be that it’s coming from the zip code and the high level of use by its residents and visitors,” he said.